ch 11 and 12

origin

• non movable part of muscle

• the attachment of a muscles tendon to the stationary bone

insertion

• The attachment of a tendon of a muscle to the movable
  bone across a joint

• Movable part

belly

middle fleshy part of the bone

biceps brachii

Origin: Scapula
Insertion: Radius
Action: pronate and flex the arm

triceps brachii

Origin:
 Scapula near shoulder joint
 Upper lateral and posterior sites of humerus
 Posterior surface of humerus
 Insertion: Back of olecranon process of ulna
 Action: Straighten (extend) the arm

lever

A rigid structure that can move around a
fixed point is called a lever
 Muscles, tendons, bones, and joints can
form three different types of levers in the
body.
 When producing movement, bones act as
levers, and joints function as the fixed point
of movement called the fulcrum.
 In a lever, the point of movement
(fulcrum) is acted on by two different
forces: Effort (muscle) and load
(Resistance).

1st class lever (few examples)

• fulcrum: atlanto-occipital joint

• locad: facial bone

• effort: muscles of the back of the neck

2nd class lever (rare)

• one in human body 

• can compare with a wheelbarrow 

• metatarsophalangeal joints are the fulcrum 

• gastronemius and soleus muscles are the effort 

• whole body weight is resistance 

3rd class lever (most common)

 The most common
 Example: Elbow Joint
 Load: Bones of hand, can add a weight
 Effort: Biceps Brachii
 Fulcrum: Elbow Joint
 Can compare with a tweezer 

prime mover (agonist)

Within opposing
pairs, the prime mover or agonist (“the
leader”) is the muscle primarily responsible
for causing the desired movement

• ex. in flexing forearm at elbow, brachialis is prime mover or agonist

antagonist

stretches and yield to effects of the prime mover

• most skeletal muscles arranged in opposing pairs at joints (antagonistic)

• ex. in flexing forearm at elbow, triceps brachii is antagonist

synergists

• Muscles used to aid or assist the
  movement of the prime mover.

• The biceps acts synergistically with the brachialis

fixator

• Type of synergist muscle that are used
  to steady or fix the proximal joints of a prime
  mover.

• Shoulder stabilizers for the forearm flexors

orbicularis oris 

• Action: Closes and protrudes lips for kissing

• Origin: Surrounding the opening of the mouth

• Insertion: The skin at the corner of the mouth

muscles of mastication

muscles that move the mandible (lower jaw)

masseter

• Origin: Maxilla and zygomatic arch

• Insertion: Mandible

• Action: Closes the mouth

muscles of mastication

 Masseter
 Temporalis
 Medial Pterygoid
 Lateral Pterygoid

muscles of facial expression 

• orbicularis oris

• orbicularis oculi

• occipitofrontalis 

• zygomaticus major 

• zygomaticus minor 

• buccinator 

• muscles are originated in fascia or bones of the skull and inserted into the skin of the face 

bells palsy

• facial paralysis 

• paralysis of muscles of the facial expression 

• due to damage to VIII cranial nerve 

• entire side of face droops in severe cases 

• sign and symptoms: unable to wrinkle forehead, close eye, or pucker lip on affected side 

extraocular muscle

• 3 pair give each eye very precise movement

• Origin: Back of the orbit

• Insertion: Different parts of the eyeball

• Action: Precise and rapid movement of the eyes

sternocleidomastoid

• origin: clavicle and sternum 

• insertion (moveable): mastoid process of temporal bone 

• action: flex and rotate head 

pectoralis major and pectoralis minor are muscles that move the pectoral girdle (shoulder)

pectoralis major:

• origin: clavicle and sternum 

• insertion: proximal humerus 

• action: adducts and medially rotates the arm at the shoulder joint 

pectoralis minor:

• origin: ribs 3-5

• insertion: coracoid process of the scapula

• action: internally rotates the shoulder

deltoid muscle 

• muscle that moves pectoral girdle (shoulder)

• origin: lateral clavicle and upper scapula 

• insertion: deltoid tuberosity on humerus shaft

• action: abducts, flexes, and medially rotates upper arm at the shoulder joint 

trapezius muscle

• muscle that moves the pectoral girdle (shoulder)

• origin: occipital bone and cervical spine 

• insertion: clavicle, scapula and lower thoracic vertebrae 

• action: supports the arm and moves the scapula up, down, in, and out 

rotator cuff

 Rotator cuff is made up of muscles and
tendons that keep the ball (head) of the
upper-arm bone (humerus) in the shoulder
socket. It also helps raise and rotate the arm
Muscles are:
 Supraspinatus
 Infraspinatus
 Teres Minor
 Subscapularis
fixed by reconstruction surgery

latissimus dorsi 

• muscle that moves pectoral girdle (shoulder)

• lower back

• origin: thoracic and lumbar vertebrae and the iliac bone

• insertion: mid-humerus

• action: drives arm inferiorly and posteriorly (swimmer’s muscle)

rectus abdominis

• anterior abdominal wall

• origin: pubic bone

• insertion: ribs and sternum 

external oblique 

• anterior abdominal wall

• origin: ribs 5-12

• insertion: iliac crest and linea alba

• actions: flexes vertebral column and compresses abdomen

diaphragm

 The main muscle of inspiration
 Origin: Inferior 6 ribs (anteriorly) and lumbar
vertebrae (posteriorly)
 Insertion: Central tendon

upper extremity muscles

Upper Extremity Muscles:
 Biceps Brachii
 Triceps brachii
 Brachialis
 Brachioradialis
 Palmaris longus
 Flexor Digitorum longus
 Thenar muscles
 Hypothenar muscles

lower extremity muscles

Lower Extremity Muscles:
 Gluteus maximus
 Biceps femoris
 Quadriceps group:
Rectus femoris, vastus lateralis
vastus intermedius
vastus medialis
 Tibialis anterior
 Gastrocnemius
 Soleus

gastrocnemius and soleus 

Muscles that plantar flex the foot at the ankle
joint (standing on “tip toes”)
 Gastrocnemius and soleus muscles function as
one – often called the calf muscle
 Origin: Femur, capsule of knee, and head of
fibula
 Insertion: Calcaneus by way of calcaneal
(Achilles) tendon

spasm 

 A sudden involuntary contraction of a single muscle within a large group of muscles
 Cause unknown
 Usually, painless

cramp

 Cramp
 Involuntary
 Often painful muscle contractions
Causes:
 Abnormal blood electrolyte levels
 Inadequate blood flow to muscles (such as in dehydration)
 Overuse and injury of the muscles

fibrosis (myofibrosis)

replacement of muscle fibers by excessive amounts of connective tissue (fibrous scar tissue) 

myosclerosis

 Hardening of the muscle caused by calcification
 Both myosclerosis and muscle fibrosis occur as a result of trauma
and various metabolic disorders

ch .12

nervous system functions 

• regulate body activities by responding rapidly using nerve impulses (action potentials) 

• initiates all voluntary movement 

• responsible for perceptions, behaviors, memories, thought, intellectual etc 

• accomplishable by excitable characteristics of nervous tissue 

organization of nervous system

• work with endocrine system

• central nervous system and peripheral nervous system 

• neurology: study of functions and disorders of nervous system 

3 fundamental steps of nervous system

• sensory function

• integrative function 

• motor function 

sensory function

Sensory receptors
detect internal and external stimuli. Then
sensory information carried to the brain
and spinal cord through cranial and spinal
nerves

integrative function

The brain or spinal
cord processes the sensory by analyzing it
and making decisions for appropriate
responses...Known as integration

motor function 

After integration, the
nervous system elicit an appropriate
motor response by activating effectors
(Muscles for contraction and glands for
secretion)

peripheral nervous system is further divided into

• somatic ns

• automatic ns 

central nervous system

brain and spinal cord

peripheral nervous system

• all nervous tissue outside the CNS

• ex. nerves, ganglia, enteric plexus, sensory receptors